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Analysis of moorings and subsea umbilicals - Sesam for moorings and risers

Improving safety and performance of deepwater floating systems through mooring, riser and subsea umbilicals analysis

Proven solution for deepwater floating systems, mooring and SURF analysis

Sesam is a proven solution for deepwater floating systems, mooring and SURF analysis (subsea, umbilical, riser, flowline). The time domain coupled analysis in Sesam provides a comprehensive and accurate analysis for mooring systems. With abundant components, different types of mooring systems, such as spread mooring, single point turret mooring, and Soft Yoke system (which is quite widely used in some shallow water areas) can be properly simulated in an efficient way. With a deeper knowledge of the solvers, thrusters and dynamic positioning (DP) systems can also be simulated and analysed simultaneously with other slender structures.


Mooring and riser analysis and verification

  • Proven solution: the mooring and riser systems of many platforms have been designed and/or verified with Sesam
  • Mooring and riser analysis methods used in Sesam have been extensively validated
  • Unique multi-body capabilities for complex field layouts involving many floaters, e.g. side-by-side moored systems, CALM analysis
  • Cross section design and global and local fatigue analysis for subsea umbilicals
  • Sesam tools for mooring and riser analysis are known in the offshore oil and gas industry for its efficiency and accuracy

Coupling effects included in mooring and riser analysis

SURF engineers must predict extreme responses and fatigue damage to mooring and riser systems under waves, wind, and current loading conditions. With Sesam you may analyse the slender structures separately or consider the coupling effect between the floater and the mooring and riser systems as the Sesam module DeepC is able to take the coupling effects and other important nonlinearities into consideration.

Analysis of deepwater installations

For deepwater installations, the riser and mooring systems greatly influence the motions of the floater. The floater and slender structures constitute an integrated dynamic system responding to the environmental loading. Because coupling effects are consistently treated, there is no need to make assumptions about the damping level (updated for each time step) which is crucial in a non-linear analysis accounting for slender structure restoring, damping and inertia forces. In other words, Sesam's software tools will increase the confidence level of riser and mooring analysis.

Subsea umbilicals and environmental conditions

Riser, moorings and the environmental conditions are defined in the Sesam module DeepC while vessel RAOs and mass/damping coefficients can be imported directly from results generated in Sesam's hydrodynamics module Wadam. The response of the risers and moorings are then computed using the non-linear solver in the Riflex module. Based on input from a global analysis, local cross-section analysis of umbilicals, helix wires, steel tubes and flexible risers may be performed using the module Helica. In the same software package, Mimosa module is the market leading mooring software for static and dynamic analysis of moored vessels and mooring systems.

As the oil and gas fields get deeper, the installaitons of deepwater platforms become more challenging. The coupling effects between a floater and its moorings become more pronounced and more important. Sesam is an excellent tool for analysis the internaction between hull, moorings and risers.

  • Andy Kyriakides ,
  • Project Manager ,
  • MODEC International LLC

Learn more about Sesam software moorings and risers

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  Sesam for moorings and risers

Sesam for moorings and risers

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  Sesam Feature Description

Sesam Feature Description

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  Sesam for moorings and risers modules

Sesam for moorings and risers modules

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